Compressor



Sept. 11, 1923. 1,467,489

B. v. .NORDBERG COMPRES S OR Filed Aug. l2, 1918 4y Sheets-Sheet'l 5Ew-Mmmm@ E. V. NORDBERG COMPRESSOR Sepp. 11, 1923. n,467,489

Filed Aug. 12, 1918 4 Sheets-Sheet 2 Si &\\\\\\\ Sept.,11,.1923.'1,467,489

B. V. NORDBERG COMPRESSOR Filed Aug. 12 1918 4 Sheets-Sheet 4 1Innern/{b11- BMWNMMu/ Patented Sept. 11, 1923.

UNITED STATES BRUNO v. NORDBERG, F MILWAUKEE, WISCQNSI.

COMPRESSOR.

Application led August 12, 1918. Serial No. 249,405.

To all whom i may concern.'

Be it known that I, BRUNO V. NORDBERG, a citizen of the United States,residing at- Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented certain new and useful Improvements inCompressors, of which the following is a specification, reference beinghad to the accompanying drawing, forming a part thereof.

This invention relates more particularly to .high duty multi-stagecompressors for compressing air or gases, especially inflaminable orpoisonous gases, to high pressures.

lts main objects are to provide reliable and efficient means forcompressing air or gases to high pressure; to minimize leakage throughpipe connections, joints, and stuing boxes and prevent escape ofinflammable or poisonous gases from a compressor into the atmosphere; tomake the pistons `and stuifing boxes leasily accessible withoutdisturbing the suction and discharge pipe connec' tions or the mountingof the cylinders; to

provide for easily disconnecting such a compresser from the engine ormotor by .which it is normally actuated and for operating it by hand inan emergency as in the case of a small compressor used in connectionwith a small internal combustion marine engine for starting andmaneuvering the engine; and generally to improve the construction andoperation of compressors of this class.

It consists `in the construction, arrangement and combination of partsas hereinafter particularly described and pointed out in the claims. l

In the accompanying drawing like characters designate the same parts inthe several figures.

Figure lis a vertical axial section of a two-cylinder four-stagecompressor embodying the invention; lFig. 2 is an axial section on theline 22, Fig. 1; Fig. 3 is an enlarged axial section of one of thesuction valves; Fig. 4 is a similar section of one of the dischargevalves; Fig. 5 is an enlarged section of the two cylinders in a plane atright angles to that of Fig. 1, showing the suction and dischargevalves, the connections of the two cylinders with intercoolers, and theleak connections; and Fig. 6 is a sectional diagram of a modificationshowing a four-stage compressor'having a single cylinder and a singlepiston.

The essential principles of the invention may be embodied in amulti-stage compressor of any desired number of stages, with a singlestepped cylinder and. a single differential or stepped piston or withtwo or more such cylinders and pistons.

Referring to Figs. 1 to 5 inclusive, showing a four-stage compressorspecially designed for compressing to high pressures,'say, 100

atmospheres or more, inammable 0r poisonous gases, there are two steppedwater jacketed cylinders, 1 and 2, each formed with twointercommunicating coaxial bores oi larger and smaller diameters, andeach of these cylinders is provided with a single `dif- Y with the boresof the Cylinders in which they.

are fitted and are lprovided with suitable packing rings.

The spaces 5 and 6 in the larger bore of the cylinder 1 on oppositesides of the larger head or step 7 of the piston 3, form the first orlow pressure stage; the space 8 in the distant end of the smaller boreof the cylinder 1 forms the second stage on one side only of the smallerhead or step 9 of the piston4 3; the space 10 in the larger bore of thecylinder 2 below the larger head or step llof the piston 4, forms thethird stage, and the space 12 in the smaller bore of the cylinder 2 be-.low the smaller head or step 13 of the piston 4 forms the fourth stage.

As shown in Fig. 5, the low pressure spaces 5 and 6 of the first stageare connected through suction valves 16 at opposite ends of the largerbore of cylinder 1 and by a pipe 17 with a holder or reservoir 18, fromwhich the gas to be compressed is drawn. The

spaces 5 and 6 are also connected through.

discharge valves 20 at opposite endsof the larger bore of the cylinder1, and by a pipe 21 with an intercooler 22. which is connected by a pipe23 and througha suction valve 24 charge valve 32 and by a pipe 33 with athird intercooler 34, which is connected by a pipe 35 and through asuction valve 36 with the space 12 of the fourth or high pressure stagein the smaller bore of cylinder 2. The space 12 is connected through adischarge valve 38 and by a pipe 39 with the compressed air or gasreceiver (not shown).

The idle space 42 in the upper end of the larger bore of cylinder 2 isconnected by a pipe 43 with a part of the compressor 1n which a lowerpressure is maintained than is produced in the working space 10 in theother or lower end of said bore, for example, as shown, with the irstintercooler 22.

The cylinders 1 and 2 are provided at their larger ends with removable,heads 45 and 46, and these heads are provided with stuiiing boxes 47 and48 for the piston rods 49 and 50 of the respective pistons 3 and 4.

A single stuing box is thus made to suffice for two stages of thecompressor, the stufing box 47 for the first or low pressure and secondstages represented by the spaces 5, 6 and 8, and the stuiling box 48 forthe third and fourth or high pressure stages represented by the spaces10 and '12.

Y To facilitate removing and replacing the pistons and to locate thestufling boxes in the most accessible positions on the compressor, wherethey may be easily observed and taken care of, the cylinders arepreferably mounted vertically as shown, with their larger ends andremovable heads uppermost.

As shown in Figs. 1 and 2, the piston rods 49 and 50 are fastened attheir upper ends in cross heads 54, which are connected by parallel rods55 extending downwardly and guided on opposite sides of the cylinders 1and 2 with cross heads 56.

The cross heads 56 have adjustable .pivot or journal bearings at theirends in slides 58 guided in vertical parallel ways 59 in the compressorframe.

The cross heads 56 are connected by rods 62 with the crank shaft 63 ofthe engine or motor.

The connecting rods 62 are preferably shouldered and threaded at theirupper ends and provided with nuts 64, so that they can be easily andquickly disconnected from the cross heads 56. Such a detachableconnection between the compressor and engine or motor is particularlyconvenient and advantageous when va single-cylinder, twostage compressor0f small size is used in connection with a small marine or internalcombustion engine for-maintaining a supply of compressed air to start ormanoeuver the engine.

In case the supply of compressed air is exhausted or reduced to apressure at which it will not start the engine, it is sometimesnecessary to disconnect the compressor from the engine and operate it byhand. For this purpose, by removingthe nut 64, thesrod 62 connecting thecross head 56 with the crank shaft 63 of the engine, is detached and thecompressor piston can be operated by f a hand lever connected with thecross head ing or pocket in the cylinder wall, a separate and reversibleseat section 67 formed with a circular series of ports 68, an annularvalve disk or plate 69, fitted to one end of the seat section 67, andnormally covering the ports 68, a spring seat or bearing 70, detachablyfastened by a central bot 71 to the seat section 67, a spiral spring 72interposed between the valve disk or plate 69 and the seat or bearing70, and a cover 73 fitting in the outer end of the opening or pocket inthe ycylinder over the valve cage. The discharge valve shown in Fig. 4is of like or similar construction, except that the cage 66 is somewhatlonger than Ithe cage 66 of the suction valve. The valve seat 67 withthe valve disk or plate 69, the spring seat or bearing 70 and the spring72, are reversed in the discharge valve, so that the valve will openoutwardly from the cylinder instead of inwardly like the suction valve,shownin Fig. 3.

To prevent leakage from the compressor cylinders into the outeratmosphere when inflammable or poisonous gases are compressed, hoods orbonnets 7 6 and 77 are bolted or detachably fastened to the removableheads 45 and 46 and form or enclose chambers around the piston rods 49and 50 over the stuing boxes 47 and 48. These chambers are connected bypiping 78 with the gas holder or reservoir 18, or with the suction inletof the compressor, in which atmospheric or a very low pressure ismaintained. The hoods or bonnets 76 and 77 are provided with stuingboxes 80 and 81, which prevent any leakage therefrom around the pistonrods into the outside atmosphere, if for any cause the pressure inthechambers formed or enclosed by the hoods or bonnets from leakage throughthe. main stuiiing-l boxes 47 and 48 is absolutely prevented.

Between the removable heads 45 and 4 6 and the larger bores of thecylinders 1 and 2 into which they are fitted, annular joints 84 areformed or provided. which are designed to withstand the highest pressurewithin the spacesv 5 and 42. These joints may be formed by accuratelyground opposing faces o f the heads and cylinder walls,

but for greatersecurity are preferably made by inserting packing ringsof other sott or compressible metal between opposing shoulders, one ofwhich may be beveled or inclined, formed on the heads and in thecylinders, these packing rings being squeezed by tightening the bolts,fastening the cylinder heads to the cylinders, to conorm with and fillor nearly fill the spaces between the opposing shoulders.

Annular chambers .86 are formed outside of the joints 84 between theremovable heads and 46, and the cylinder walls, and these chambers areconnected by the piping 78 with the gas holderor reservoir 18 or withthe main inlet of the compressor. The chamber formed or enclosed by thehood or bonnet 77 over the stutiing box 48 communicates through anLopening 88 with the annular chamber 86 formed in the head 46, so that asingle connection with the piping 78 suiiices for both of said chambers,as shown in Fig. 5, While separate connections with said piping are madefor the chamber formed by the hood or bonnet 76 and the annular chamber86 in the head 45. v

Outside of the annular chambers 86, annular joints 90 are formed betweenthe heads 45 and 46 and opposing walls of the Vcylinders 1 and 2. Thesejoints preferabiy consist of rubber or other soft packing com- Dressedbetween opposing shoulders or faces of the heads and cylinders, andabsolutely prevent any leakage from the chambers 86 into the outsideatmosphere, if for any cause the pressure in said chambers shouldslightly exceed that of the atmosphere or that maintained in the gasholder or reservoir 18.

As shown in Figs. 3, 4 and 5, like or similar joints 84 and 90 withintervening annular chambers 86 are formed between the valve covers 73,valve cages 66 and 66 and the opposing walls of the cylinder pockets oropenings in which they are fitted, and these chambers are also connectedby the piping 78 with the as holder or reservoir 18 or with the maininlet of the compressor.

For convenience of construction the cylinders 1 and2 are preferablyprovided at their smaller ends, as shown, with separate heads 92 and 93,which are permanently bolted to the cylinders and between which and thecylinders, tight joints are formed. These joints like the joints 84between the removable heads 45 and 46, at the upper larger ends of thecylinders, may consist of copper or other soft metal packin ringscompressed between opposing shou ders of the heads and cylinders, andare easily made and kept tight since the heads 92 and 93 are inrequentlyor never removed from the cylm ers.

A compressor of any desired number of stages, two or more, may be builtupon the same principle and according to the invencopper or tiongashereinbefore described, with a single cylinder 1 and a single piston 3',as diay.

grammatically shown in Fig. 6.

In the operation of the compressor, whether it comprises two or morestages, the air or gas compressed in the spaces 5 and 6 ot the first orlow pressure stage,l is discharged therefrom through the vvalves 20 intothe first intercooler 22, in which it is cooled approximately to theinitial temperature of the air or gas and from which it is drawn at thattemperature through the suction valve 24 into the space'8 of the secondstage, or in the case of a two-stage compres sor, the high pressurestage, from which it is discharged through the valve 26 and pipetemperature, and from which it is drawn through the pipe 29 and suctionvalve 30 into the space 10 in the larger bore of the cylinder 2,constituting the third stage of compression, F rom the space l() of thethird stage the more highly compressed gas or air is discharged throughthe valve 32 and pipe 33` into the third intercooler 34, in which it isagain cooled to approximately its initial temperature and from which itis drawn through the pipe A35 and valve 36 into the space 12 of the lastor high pressure stage.

From .the fourth or high pressure stage, the highl compressed air or gasis discharged t rough the` valve 38 and pipe 39 into the receiver.

It will be'observed that the piston head or* step 7 of the low pressurestage is double acting, while each of the other piston heads or Isteps9, l1 and 12, is single acting, and that there is but one stuffing boxfor each cylinder comprising two stages, and each .stuifing box issubjected only t'o the pressure of the first or low pressure stage. Anyyleakage which may occur past the acking' rings of the piston head orstep 9 rom the space 8 of the second stage into the s ace 6 of the firstor low pressure stage, wou d slightly increase the pressure in the space6 and correspondingly increase the power required for' compression oftheair or gas, but would not reduce the capacity of the compressor.-

The space42 in the largerbore of the cylinder 2, which has no valves andis connected with the intercooler 22 between the first and secondstages, does not contribute to the compression of the air'or gas. Thelow pressure of. the first stage is maintained in this space in orderto'minimize any leakage between the thirdand second stages by reducingthe pressure difference between the spaces 10 and'42.

In a comp-ressor of any desired number of stages, two or more, theseveral stages may all be arranged in axial alignment with one another,the steps of the cylinder for the several stages diminishing in diameterfrom one end of the cylinder to the other, so that there will be no idlecylinder spaces, thus making the machine more compact and tending toavoid leakage between adjoining stages, as shown for exam le, in case ofa two stage compressor, by Fig. 2, and in case of a four stagecompressor by Fig. 6. The cylinder barrel for the several stages is castin one piece or in sections connected with each other by permanentjoints, thereby avoiding 'loose or insecure joints which are liable toleak, thus allowing gas to escape into the surrounding atmosphere andimpairing the eicienc of the compressor.

By making the piston of the first or low pressure stage double acting,its diameter and hence the greatest diameter of the cylinder arematerially reduced, thus further tending to avoid leakage between thefirst and second stages and effecting a. saving in ythe cost of thecompressor.

The space 42 might be connected with the main inlet of the com ressor,but in that case the leakage from tliie third stage, whatever it mightbe, would cause a loss of capacity, which is not the case with thearrangement shown and described, since any leakage between the s aces 10and 42 would not reduce the capacity of the compressor, but wouldslightly increase the power required to operate 1t.-

Any leakage of gas past the joints 84 between the removable cylinderheads 45 and 46 and cylinders and between the valve covers 73 and thewalls of the valve openings in the cylinders, is trapped 'in the annularchambers 86, and drawn therefrom through the piping 78 into the gasholder 18 or main inlet of the compressor.

Any gas leakage through the main stuffingk boxes 47 and 48 from the lowpressure spaces 5 and 42 into the chambers formed by the hoods orbonnets 76 and 77, is likewis/e withdrawn therefrom through the piping78 into the gas holder 18 or main inlet of the compressor. t

In this way, inflammable or poisonous gases are absolutely-preventedfrom escapvving from the compressor into the surround;`

ing atmosphere.

The principal and 'essential features of the invention (may, ashereinbefore stated, be embodied in a compressor of any desired numberof stages with a single stepped cylinder l', having intercommunicatmcoaxial bores of different diameters, an a single differential orstepped piston 3', as shown in Fi 6 without loose or insecure joints andid e cylinder spaces between the stages.

compression, the larger bore of the low pressure stage being provided ateach end and each smaller bore of a higher pressure stage being providedat its distant end only with suction and discharge valves, a removablehead fastened to the larger end of the cylinder and provided with astuffing box, and a stepped piston fitting the several bores of thecylinder and provided at its lar er end with a rod passing through thestuilmg box in the removable cylinder head, thei larger step of thepiston being double acting and cach small-er step single acting, and thepiston being removable through the larger end of' the cylinder withoutdisturbing the mounting and suction and discharge pipe connections ofthe cylmder.

2. In a compressor the comblnation of a cylinder permanently yclosed atits smaller .tuting' separate stages of compression, thel larger bore ofthe low pressure stage being provided at each end andv each smaller boreof ay higher pressure stage being providedI at its distant end only withsuction and discharge valves, a removable head fastened to the largerend of the cylinder and provided with a stuiiing box, anda steppedpiston fitting the several bores of the stepped -cylinder and providedat its larger end with a rod passing through the stufling box intheremovable cylinder head, the piston removable through the larger endofthe cylinder without disturbing the mounting and suction and dischargepipe connections of the cylinder, and all spaces within the cylinderbeing active compression spaces.

3. In a compressor the combination of two cylinders each havingintercommunieating bores of larger and smaller diameters correspondingwith lower and higher stages ofcompression, each end of the. first stagecylinder bore anda single end of each succeeding intermediate stage andof the last cylinderand provided at its larger end with tained than is arod passing through the stuffing box in the removable head, thedischarge of each intermediate stage being connected with the inlet ofthe next higher stage, and the idle end of the larger bore of thesmaller cylinder bein connected with a part 'of the compressor 1n whicha lower pressure 1s mainsaid bore.

4. In a compressor the combination of a cylinder having a removable headprovided with a stuing box, a piston fitting the cylinder and providedwith a rod passing through the stuiling box in the removable head, and abonnet forming with said head a chamber aroundthe piston rod over andenclosin the stuiiing lbox in the removable head, said chamber beingconnected with the inlet to the compressor to collect gas which may leakthrough the stuiing box to be conducted back to the inlet of thecompressor.

5. In a'compressor the combination of a cylinder, a piston fitting saidcylinder, a tted to the cylinder, two separated annu ar joints betwenthe cylinder and itsremovable head, and 4an annular chamber betwen thejointsand opposing walls of the cylinder and removable :head

connected with the `inlet to the compressor.

6. Inacompressor the combination with a cylinder provided'with a valvechamber, vof a removable cover fitted to said chamber,

-spaced fluid-tight annular joints between the cover and wall of thevalve chamber, and an annular chamber between said joints conj nectedwith the inlet to the compressor.

7. In a com ressor the combination with Y a cylinder having one openend, of a remov-` able head fitted to the .open end of the cylinder,.spaced annular joints between the head and cylinder wall, and anannular chamber located between said joints vand connected with theinlet to the compressor.

8. In a compressor the combination with produced in the other end ofV-able covers fitted to the valve openings,

spaced' annular joints betwen the head and covers and the cylinder, andannular chambersl located betweensaid joints and connected with theinlet to the com ressor.

9. -In a compressor the combmation of a cylinder provided around anopenin into its bore with spaced annular shoul ers, a closure fittinginto the opening and formed with spaced annular shoulders opposing theshoulders around the cylinder opening, a soft metal packing interposedbetween the inner shoulders, elastic packing vinterposed between theouter shoulders,.and an annu'- lar chamber located between the jointsformed by saidshoulders and packing and connected with the inlet to thecompressor.

10. In a compressor the combination of a cylinder having adjoiningcoaxial bores each provided for a single stage of compression,

the bore of the low pressure stage bein pro` vided at each end with'suction an vdiacharge valves, and the adjoining smaller bore beingprovided at its distant end only withsuction and discharge ,valve's, all'spaces within the cylinder being active com ression spaces, a headdetachably fastene to the larger end of the cylinder and provided with astuilingv box, and a stepped piston fitting the bores of the cylinderand provided at its larger end with a rod passing through the .i

BRUNO V. NORDBERG. I

